You just have to love this “syntax”
Story

#features/discussion.feature
Scenario: I add to an discussion
    Given I am logged in
    And a "Discussion" exists for "Festival" "1"
    And I am on "Festival" "1"
    When I fill in "Text" with "Halloo"
    And I press "Send"
    Then I should be on "Festival" "1"
    And I should see "Halloo"

Steps

#features/step_definitions/common_steps.rb
# On page/record
Given /^I am on "([^"]*)"$/ do |path|
  visit path
end

Then /^I should be on "([^"]*)"$/ do |path|
  current_path.should == path
end

Given /^I am on "([^"]*)" "([^"]*)"$/ do |model,number|
  visit polymorphic_path(record_from_strings(model,number))
end

Then /^I should be on "([^"]*)" "([^"]*)"$/ do |model,number|
   current_path.should == polymorphic_path(record_from_strings(model,number))
end

# Existing
Given /^a "([^"]*)" exists for "([^"]*)" "([^"]*)"$/ do |associated,model,number|
  record = record_from_strings(model,number)
  record.send(associated.underscore+'=',valid(associated))
  record.save!
end

# Login
Then /^I should be logged in$/ do
  should be_logged_in
end

Given /^I am logged in$/ do
  visit 'login'
  fill_in 'email', :with=>'quentin@example.com'
  fill_in 'password', :with=>'test'
  click_button 'Login'
end

# Support
def current_path
  response.request.request_uri
end

def record_from_strings(model,number)
  model.constantize.find(:first,:offset=>number.to_i-1)
end

env.rb

#features/support/env.rb
#load all fixtures
include AuthenticatedTestHelper #restful_authentification
include ValidAttributes #http://github.com/grosser/valid_attributes